Hydrogenation of esters is an important process. It is often used to manufacture alcohols on an industrial scale for numerous applications, including plasticizer and polyester synthesis. Industrially, ester hydrogenation is typically performed with heterogeneous catalysts like copper chromite under very harsh reaction conditions (250-300° C. and 2000-5000 psig of H2 pressure). These harsh conditions often lead to lower selectivity to the desired alcohol product by forming multiple side products. From the energy cost and safety standpoint, developing a homogeneous catalytic system for ester hydrogenation is highly desirable, because of its potential to be effective under much milder conditions and achieving higher selectivity.
Efforts have been made toward this end. However, such efforts suffer from one or more drawbacks, such as requiring the use of expensive precious metal catalysts, high temperatures, and/or high hydrogen pressures.
Thus, there is a need in the art for a process for hydrogenating esters that does not suffer from these drawbacks.
The present invention addresses this need as well as others, which will become apparent from the following description and the appended claims.